Leisure-time and occupational physical activity and risk of long-term sickness absence from mental disorders: a prospective cohort study.

Abstract

This study examined whether leisure-time physical activity (LTPA), occupational physical activity (OPA), and their combination are associated with risk of mental disorder-related long-term sickness absence (LSA). This cohort study included 38,120 Japanese employees aged 20-59 years from the Japan Epidemiology Collaboration on Occupational Health Study. Baseline assessments were conducted primarily in 2011, with follow-up from 2012 through 2024. LTPA and OPA levels were self-reported at baseline. LSA (≥30 consecutive days) due to mental disorders was medically certified by physicians. Cox regression estimated hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for demographic, lifestyle, occupational, and health-related factors including depressive symptoms. During a mean follow-up of 9.2 years, 1,032 participants (2.7%) experienced LSA from mental disorders. LTPA showed an inverse but non-linear association with LSA risk (p for non-linearity=0.042) with lower risk apparent at low activity; activity below recommended levels was associated with reduced risk (HR 0.72, 95% CI 0.55-0.93). The inverse association of LTPA was evident when restricted to depressive disorders as the outcome (p for trend=0.029) and among sedentary workers (p for trend=0.027), although the interaction by OPA was non-significant (p=0.14). Higher OPA was linearly associated with lower risk (HR for physically active vs sedentary work = 0.50, 95% CI 0.37-0.69; p for linear trend<0.001). LTPA showed inverse associations with mental disorder-related LSA, most evident for depressive disorders. Higher OPA was associated with reduced risk of mental disorder-related LSA, not clearly supporting the physical activity paradox.